Drogue deployment for lighter than air vehicle descent

ABSTRACT

The technology relates to techniques for drogue deployment for a lighter than air (LTA) vehicle descent. A drogue deployment system for an LTA vehicle descent can include a drogue comprising a drogue parachute coupled to a carrier. A spring can be configured to launch the drogue from a launch tube directed outward from an apex of the LTA vehicle in an acute angle from a horizontal plane. A core can be placed around the launch tube and placed around the spring, the core compressing the spring and holding the spring in a compressed state prior to deployment, and a riser can couple the carrier to the envelope of the LTA vehicle. In some cases, the drogue deployment system can comprise two or more drogues, wherein intervals between the two or more drogues can be selected such that horizontal components of drogue deployment forces approximately cancel out.

BACKGROUND OF INVENTION

Fleets of lighter than air (LTA) aerial vehicles are being consideredfor a variety of purposes, including providing data and networkconnectivity, data gathering (e.g., image capture, weather and otherenvironmental data, telemetry), surveillance, and systems testing, amongothers. LTA vehicles can utilize a balloon envelope or a non-rigid hullfilled with a gas mixture that is lighter than air to provide lift. Thegas is released from the balloon envelope or a non-rigid hull toinitiate a planned or unplanned descent of the LTA vehicle.

Drogue parachutes are parachutes that are deployed from rapidly movingobjects to slow the object, or to provide control and stability. Forexample, drogue parachutes are used to shorten the landing of airplanes(e.g., when landing on aircraft carriers), and to slow fast moving landvehicles (e.g., drag racing vehicles and vehicles used to break landspeed records). Drogue parachutes have also been used to stabilize thedirection of an object in flight, such as for certain types of grenades,or spacecraft upon reentry. Drogue parachutes can also be used to deploya main parachute (e.g., for a person skydiving) wherein the drag forcegenerated by the drogue is used to open the main parachute.

BRIEF SUMMARY

The present disclosure provides techniques for drogue deployment for alighter than air (LTA) vehicle descent. A drogue deployment system foran LTA vehicle descent can include a drogue comprising a drogueparachute coupled to a carrier, wherein the drogue parachute isconfigured to be wrapped around the carrier prior to deployment and toopen after deployment; a launch tube coupled to an apex of an envelopeof the LTA vehicle, the launch tube directed outward from the apex in anacute angle from a horizontal plane; a spring winding around the launchtube, the spring configured to launch the drogue; a core placed aroundan outer circumference of the launch tube and placed around the spring,the core compressing the spring and holding the spring in a compressedstate prior to deployment; and a riser coupling the carrier to theenvelope of the LTA vehicle, wherein: the carrier is placed over andsubstantially covers the launch tube and the core, the carriercomprising a narrower circumference in a portion beyond the core suchthat the spring can push the carrier off of the launch tube upondeployment; and the riser is connected to the carrier in a coiledmanner. In an example, the drogue deployment system deploys two or moredrogues positioned at intervals away from one another; and the two ormore drogues are each configured to deploy from the drogue deploymentsystem at acute angles from a horizontal plane. In another example, theintervals between the two or more drogues and the acute angles areselected such that horizontal components of drogue deployment forcesused to deploy the two or more drogues approximately cancel out. Inanother example, the intervals between the two or more drogues and theacute angles are selected such that the drogues do not make contact withthe apex of the lighter than air vehicle after the drogues are deployedand before the drogue parachutes are opened. In another example, thedrogue deployment system deploys two drogues positioned at intervals of180°, three drogues positioned at intervals of 120°, four droguespositioned at intervals of 90°, or six drogues positioned at intervalsof 60°. In another example, the coiled riser is contained in a riserdrum attached to the drogue carrier and unspools from the riser drumafter the drogue is deployed. In another example, the drogue isconfigured to pull up on the envelope with respect to a payload of theLTA vehicle, thereby reducing the chance that the envelope will impactwith the payload of the LTA vehicle during descent.

An LTA vehicle can include an envelope configured to hold gas and air;and a drogue deployment system, comprising: two or more drogues eachcomprising a carrier and a drogue parachute, each drogue directedoutward from the apex in an acute angle from a horizontal plane at aninterval away from another of the two or more drogues; two or morelaunch tubes coupled to an apex of the envelope; two or more springs,each spring winding around one of the launch tubes; two or more cores,each core placed around an outer circumference of the one of the launchtubes and placed around one of the springs, each core compressing one ofthe springs and holding that spring in a compressed state prior todeployment; and two or more risers, each riser configured to couple oneof the carriers to the apex of the envelope; wherein: each of thecarriers is placed over and substantially covers one of the launch tubesand one of the cores; each of the carriers comprises a narrowercircumference in a portion beyond one of the cores such that the springscan push the carriers off of the launch tubes upon deployment; each ofthe drogue parachutes is coupled to one of the carriers, and isconfigured to be wrapped around one of the carriers prior to deploymentand to open after deployment; each riser is connected to one of thecarriers in a coiled manner; and the interval between each of the two ormore drogues and the acute angles are selected such that horizontalcomponents of drogue deployment forces used to deploy the two or moredrogues approximately cancel out. In an example, the intervals betweenthe two or more drogues and the acute angles are selected such thathorizontal components of drogue deployment forces used to deploy the twoor more drogues approximately cancel out. In another example, theintervals between the two or more drogues and the acute angles areselected such that the drogues do not make contact with the apex of theLTA vehicle in a time frame after the drogues are deployed and beforethe drogue parachutes are opened. In another example, the droguedeployment system deploys two drogues positioned at intervals of 180°,three drogues positioned at intervals of 120°, four drogues positionedat intervals of 90°, or six drogues positioned at intervals of 60°. Inanother example, the coiled riser is contained in a riser drum attachedto the drogue carrier and unspools from the riser drum after the drogueis deployed. In another example, the drogues are configured to pull upon the envelope with respect to a payload of the LTA vehicle, therebyreducing the chance that the envelope will impact with the payload ofthe LTA vehicle during descent. In another example, the LTA vehiclefurther includes a payload comprising a solar panel, a broadbandcommunications unit, and a terminal, wherein the drogues are configuredto pull up on the envelope with respect the payload, thereby reducingthe chance that the envelope will impact with the solar panel, broadbandcommunications unit, or terminal of the LTA vehicle during descent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified schematic of an example of a portion of an LTAvehicle in side view, comprising a drogue deployment system, inaccordance with some embodiments.

FIGS. 2A, 2B and 2C are simplified schematics of different examples ofapex plates as viewed from above, each containing multiple drogues whichare arranged to deploy in directions with acute angles from a horizontalplane from an apex of an LTA vehicle, in accordance with someembodiments.

FIG. 3 is a simplified schematic of an example of a portion of a droguedeployment system in side view, in accordance with some embodiments.

FIG. 4 is a simplified schematic of an example of a portion of a droguedeployment system in projection view, in accordance with someembodiments.

FIGS. 5A-5D are simplified schematics, each in perspective view, showingan example of a drogue deployment from an LTA vehicle at differentinstances in time, in accordance with some embodiments.

FIGS. 6A-6B are simplified schematic diagrams of example LTA unmannedaerial vehicle (UAV) systems incorporating the present drogue deploymentsystems, in accordance with some embodiments.

FIG. 7 is a flowchart for a method for deploying drogues from an LTAvehicle, in accordance with some embodiments.

FIG. 8 is a flowchart for a method for loading drogues in a droguedeployment system for an LTA vehicle, in accordance with someembodiments.

The figures depict various example embodiments of the present disclosurefor purposes of illustration only. One of ordinary skill in the art willreadily recognize from the following discussion that other exampleembodiments based on alternative structures and methods may beimplemented without departing from the principles of this disclosure,and which are encompassed within the scope of this disclosure.

DETAILED DESCRIPTION

The Figures and the following description describe certain embodimentsby way of illustration only. One of ordinary skill in the art willreadily recognize from the following description that alternativeembodiments of the structures and methods illustrated herein may beemployed without departing from the principles described herein.Reference will now be made in detail to several embodiments, examples ofwhich are illustrated in the accompanying figures.

The invention is directed to the use of drogues deployed from an apex(e.g., from an apex plate) of a lighter than air (LTA) vehicle to managethe descent of a balloon envelope or a non-rigid hull (hereinafter“envelope”) of the LTA vehicle. The drogues can contain a carrier and adrogue parachute attached to the carrier. Such drogues may be deployedjust prior to, during, or after the envelope of an LTA vehicle is burstor cut (or otherwise fully or partially deflated), and the drogues canbe configured to assist the LTA vehicle make a controlled descent,whether planned or unplanned.

LTA vehicles that use the present systems and methods can includepassive LTA vehicles (e.g., floating stratospheric balloons, otherfloating or wind-driven vehicles), or powered LTA vehicles (e.g.,balloons and airships with some propulsion capabilities). The envelopesof LTA vehicles can contain a gas (e.g., hydrogen and/or helium) andair. The present drogue deployment systems and methods can, in someembodiments, provide additional lift to the envelope as it is deflatingduring the descent of the LTA vehicle. This has the effect of pulling upon the envelope with respect to the payload of the vehicle, which helpskeep the LTA vehicle from being damaged during descent. For example, thedrogues can help keep the envelope above the payload (with respect tothe ground), which reduces the chance that the envelope will impact withthe payload and damage components of the payload. In some embodiments,the present LTA vehicles also have one or more main parachutes, whichdeploy after the LTA vehicle descent is initiated and slow the descentvelocity of the LTA vehicle during a planned or unplanned descent. Themain parachute(s) slow the descent velocity of the LTA vehicle such thatthe payload is not damaged (or the damage to the payload is reduced)when the LTA vehicle lands.

In some examples, drogues described herein may be deployed prior to aplanned descent (e.g., intentional termination of flight). In otherexamples, such drogues may be deployed at or soon after a planned orunplanned descent (e.g., an unexpected burst or other unexpected failurerequiring immediate termination of flight).

In some cases, the flight is terminated (e.g., the LTA envelope bursts),and the drogues are deployed from an unsupported (or a minimallysupported) apex plate. After the flight is terminated and the LTAvehicle begins to descend, the drogues can be configured to pull up onan apex of the envelope. In some cases, more than one drogue deploymentsystem can be coupled to the envelope, and the drogues can pull up onthe envelope at more than one location. The force(s) provided by thedrogues can keep the envelope away from the payload and other componentsof the LTA vehicle. Without the drogues providing an upward force on theenvelope after flight termination the different components of the LTAvehicle can move erratically, which can cause damage to the components.For example, the envelope and/or tendons between the apex of theenvelope and a base of the envelope (e.g., at an altitude controlsystem) can impact sensitive components (e.g., communications systems)on the payload causing damage. The drogues help prevent such damage bykeeping the envelope away from the payload.

Additionally, the force(s) provided by the drogues can cause theenvelope to elongate and help keep the LTA vehicle more streamlined(i.e., have less drag) during descent. In some cases, an LTA vehicle hastwo main sections, an envelope and a payload, which are connected to oneanother by a connection component (e.g., a down connect). In some suchcases, the drogues ensure that the envelope section has more drag and aslower terminal velocity than the payload section, which results in theenvelope section staying above the payload section during descent andalso results in the envelope section elongating because it is pulled upby the drogues (at the apex of the envelope) and down by the payload (atthe base of the envelope). During the initial phases of the descent(i.e., the phases of descent before the main parachute(s) are deployed),the streamlined LTA vehicle can have a faster descent speed than an LTAvehicle with an envelope that is unsupported by the present droguesystems and methods, which can be advantageous for several reasons. Forinstance, a faster descent speed in the initial stages of descent canimprove the accuracy of predicting a landing location. Once a flight isterminated, a prediction of the landing location can be useful becauseit can enable one to more easily recover the LTA vehicle after it lands.If the LTA vehicle is descending more slowly, then winds have a greaterchance to affect the landing location of the LTA vehicle than if the LTAvehicle is descending more quickly. The main parachutes can then bedeployed as late in the descent as possible to ensure that the descentvelocity of the LTA vehicle is slow enough to avoid damage (e.g., due todynamic pressure and/or impacting the ground upon landing) and toimprove the accuracy of predicting the landing location. Additionally,for high altitude LTA vehicles (e.g., ones that fly in the stratosphere)it can be advantageous to descend more quickly through airspacealtitudes used by airplanes because it will cause less disruption toairplanes.

The acceptable descent velocity for an LTA vehicle during the initialstages of descent (before the main parachute(s) open) can vary and islargely based on maximum acceptable dynamic pressure. Dynamic pressureis defined by the equation q=0.5*air density*v2, where q is dynamicpressure, v is the descent velocity, and air density increases asaltitude decreases. The drogues can also be configured to provide enoughdrag such that a terminal velocity of the LTA vehicle during descentdoes not exceed a certain dynamic pressure (e.g., that could causedamage to components of the LTA vehicle). There is a potential trade offin drogue design (e.g., for drogue parachute size), because a drogueparachute requires a minimum dynamic pressure to inflate, but as thedynamic pressure increases the drogues become more effective and providemore drag, which slows the LTA vehicle and reduces the dynamic pressure.

A drogue may be configured to provide drag on a balloon or non-rigidhull envelope during an LTA vehicle's descent to help prevent theenvelope from collapsing on a payload or other underlying structureprematurely. A drogue may comprise a drogue parachute and a carrier. Insome cases, the drogue parachute is wrapped around and/or over thecarrier. The carrier can be configured to be placed over a launch tubeand a core. The launch tube is mounted onto a structure on the apex ofthe envelope (e.g., an apex plate, or a load ring on an apex plate) atan acute angle from a horizontal plane. In some embodiments, a springmechanism is used in conjunction with the launch tube to launch (ordeploy) the drogue (i.e., parachute and carrier) off the core. Thepropulsion system(s) used to deploy the drogues can be spring systems,compressed gas systems, small explosive devices (i.e., squibs), smallhot gas generators (i.e., small rocket motors), and/or any mechanism ordevice which would convert stored energy to linear kinetic energy, indifferent embodiments. At the base of the carrier may be a housing(e.g., a riser drum) containing a riser (e.g., coil of ribbon, rope,string), where the riser is coupled on one end to the carrier and on theother end to the apex, either directly or indirectly (e.g., by a mount,or other structure coupled to the apex of the envelope). In someexamples, the riser may comprise a ribbon with a sufficient strengthprofile to withstand a range of forces from drogue parachute deployment.The length of the riser can be from 70 feet to 100 feet, or from 20 feetto 200 feet. The riser can be made from a material such as a Kevlar(i.e., fibers containing polyparaphenylene terephthalamide) or Dyneema(i.e., fibers containing ultra-high-molecular-weight polyethylene)ribbon. In some cases, a riser shaped like a ribbon is used instead of aline-shaped riser because a riser shaped like a ribbon can have improveddrag characteristics. For example, a riser shaped like a ribbon canproduce more lift for itself than a line-shaped riser, thereby holdingits own weight in a freefall condition and limiting the risk that theriser becomes entangled (e.g., with itself or other components of theLTA vehicle).

In some embodiments, springs are used to launch (or deploy) the droguesthat have spring constants from 2.5 kN/m to 5.5 kN/m, or from 1 kN/m to10 kN/m. The spring energy, which is proportional to the spring constanttimes the spring compression squared, can be configured to be largeenough to launch the drogues an acceptable distance upon deployment. Forexample, the spring energy can be about 30 J, or from 10 J to 100 J.However, the spring energies needed can vary considerably with theapplication (e.g., with the size and mass of the drogue being deployedto manage the descent of an LTA vehicle), and therefore can be less than10 J or greater than 100 J in some applications. In some embodiments,the core, launch tube and spring are configured to compress the springand hold the spring in a compressed state prior to placing the drogue(i.e., the drogue carrier and drogue parachute) onto the launch tube andcore. This can be accomplished using a strap that holds the spring in acompressed state after the spring is compressed. The strap is thenreleased or cut by a deployment mechanism, which allows the spring todecompress and deploy the drogue. For example, the strap can be fedthrough a squib component that is configured to cut the strap to deploythe drogue. In some cases, the drogue carrier also clips onto the core,which locks the drogue in place. In some embodiments, this clipmechanism is also unlocked by the drogue deployment mechanism, while insome embodiments, the core remains coupled to the carrier and travelswith the drogue after the drogue is deployed. Examples of droguedeployment systems are described further herein. In some cases, thespring is covered with a sleeve, which can prevent the riser frombecoming tangled with the spring after the drogue is deployed. In somecases, the drogues each contain a safety system to prevent the droguefrom being deployed prematurely. For example, mechanical locks or pinscan be attached to portions the drogue, which are removed prior toflight, to prevent the drogue from deploying before the LTA vehicle isflown.

In some cases, the carrier is weighted to stabilize the drogue afterdeployment and before the drogue parachute opens. For example, aweighted carrier can keep the bottom of the drogue orientedapproximately downwards (relative to the ground) such that the parachutefaces the correct direction when it is opened from the top of thedrogue. This can be helpful, because at low dynamic pressures (e.g.,when the descent velocity of the balloon is low and/or at high altitudeswhen the air pressure is low) the drogues do not have enough airflow tofully inflate, and the mass of the carrier can help keep the drogue inthe right orientation to receive incoming air. In some examples, thecarrier may be weighted such that the drogue drops downward relative tothe apex (e.g., below a horizontal plane, or altitude, of the apex) upondeployment and before the drogue parachute opens. The weighted carriermay be carried upward relative to the apex along with the drogueparachute (e.g., above the horizontal plane, or altitude, of an apex ofthe vehicle) after the drogue parachute has opened sufficiently, sincethe carrier is coupled to, and hanging downward from, the opened drogueparachute. In some cases, the mass of the carrier is from 10 g and 200g, or from 10 g and 100 g, or is about 50 g. In some cases, the mass ofeach drogue (e.g., including the carrier and parachute) is from 500 g to2 kg, or from 500 g to 1.5 kg, or is about 1 kg. In some cases, thecarrier is relatively light, has a relatively low amount of drag, and/orhas a relatively high mass density compared to the drogue parachute.

The drogues (i.e., drogue carriers with drogue parachutes attached) aredeployed using a drogue deployment system. The system imparts a droguedeployment force to deploy each of the drogues, thereby moving them awayfrom the apex of the LTA vehicle. In some embodiments, each drogue isdeployed in a direction that is at an acute angle from a horizontalplane intersecting the apex of the LTA vehicle, or at an angle that isfrom 0° to 30°, or 0° to 45° or from 0° to 60°, or from 0° to 90°, orfrom about 30° to about 50°, or about 38.5°, or about 40°, or about 45°,above a horizontal plane intersecting the apex of the LTA vehicle, orsubstantially horizontally from the apex of the LTA vehicle. The drogueparachutes can then be opened after drogue deployment. In someembodiments, the drogues contain mechanisms for opening the drogueparachutes. For example, a pin can be configured to hold the drogueparachute in place on the carrier, and the drogue can contain amechanism that pulls the pin after the riser is uncoiled (e.g., byattaching the pin to the riser near the end of the riser (e.g., about 6inches from the end of the riser) that is attached to the carrier),which allows the parachute to open via the force of air flow as the LTAvehicle descends. For example, a harness can be used to hold the drogueparachute closed (e.g., by wrapping around the drogue) and a pin can befed through the harness such that when the pin is pulled the harness cancome undone thereby allowing the drogue parachute to open. In somecases, the harness can contain a strap with a loop at either end, andthe loops can be positioned around the pin such that the harness is heldin place by the pin. In such cases, before opening the parachute, thestrap is wrapped around the drogue parachute holding it closed, andafter the pin is pulled (e.g., by the riser as it is uncoiling) thestrap is no longer held in place and the parachute can open. In othercases, a drogue parachute can be opened by removing a mesh covering(e.g., by attaching the mesh covering to the riser near the end of theriser that is attached to the carrier). The drogue parachute can beopened when reaching the end of the riser, or at a certain predetermineddistance from the LTA vehicle, or at a certain predetermined time afterthe drogue is deployed, or based on another event (e.g., upon reaching apredetermined descent velocity).

As the LTA vehicle descends and the drogue parachutes begin to open, thedrogue parachutes are configured to catch air to open more fully. As thedrogue parachute opens more fully, the drogue may surf a wake ofturbulence (e.g., caused by the descending LTA vehicle), bringing thecarrier substantially upward with it. The wake can contain air currentsmoving in a substantially upward arching trajectory resulting from thesubstantially downward trajectory of the LTA vehicle in descent. In someembodiments, the drogue surfs a wake causing the drogue to move outward(i.e., away from the apex of the LTA vehicle). In some embodiments, asthe balloon shrinks, the wake gets smaller, and the carriers moveinwards and rise upwards. In some embodiments, deploying the droguesfrom the apex of the LTA vehicle in a substantially horizontal directionenables the drogues to surf the wake, which prevents the drogues fromgetting too close to the LTA vehicle (e.g., and falling back onto theapex plate before the parachute opens). In some cases, the risers arelong enough such that the drogues can be located outside of theturbulence caused by the descending LTA vehicle. The drogue parachutesdescribed herein can have diameters from 0.5 m to 5 m, from 1 m to 5 m,from 1 m to 3 m, or from 2 m to 3 m. In other embodiments, the drogueparachutes can have larger or smaller diameters than those listed,depending on factors such as the number of drogues used, and the sizeand mass of the LTA envelope and/or of the LTA vehicle.

At least two drogues may be deployed at an acute angle from a horizontalplane (e.g., substantially horizontally), and substantially oppositeeach other, from an apex of an LTA vehicle. The substantially horizontaldirection of deployment can prevent the drogues from falling back, orfrom being pulled back, onto the apex of the LTA vehicle prior to thedrogue parachutes opening. Deploying two or more drogues in opposingdirections (e.g., at approximately the same time) balances the forcesbetween the deploying drogues, which minimizes the need for othermechanisms to balance the force of deploying any one drogue. Such droguedeployment systems that utilize multiple drogues can improve thedistance a drogue can be deployed for a given drogue deployment force(as opposed to systems where the drogue deployment forces are notbalanced). Such drogue deployment systems can also assist with deployingdrogues from LTA vehicles that are partially deflated because thedrogues are deployed in a substantially horizontal direction and thereaction forces of deploying the drogues in such systems are balancedthereby causing less total force on the partially deflated LTA vehiclecompared to drogue deployment systems that do not launch the droguessubstantially horizontally and/or are not configured to balance thedrogue deployment forces. Multiple drogues are also beneficial becauseif one or more drogues are damaged (e.g., when an LTA envelope fails)the remaining drogues can still be deployed.

In some examples, drogue deployment may be triggered manually orautomatically. In some examples, deployment may be triggered usingsquibs, mechanical cutting mechanisms (e.g., triggered by displacementdue to the turbulence or vibrations associated with an envelopebursting), timed UV degradation, or other mechanisms. Not to be limitedby theory, when an LTA envelope fails, it can cause the components ofthe LTA vehicle to experience large forces, e.g., from 20 G's to morethan 100 G's. These large acceleration forces caused by the envelopefailing can be used to trigger a mechanical triggering mechanism (e.g.,an inertial triggering mechanism) to launch a drogue. In differentdesigns, inertial triggering mechanisms can use blades, pins that drop,springs, moving bearings, and/or squibs (i.e., miniature explosivedevices) to launch a drogue based on an experienced acceleration. Forexample, a trigger mechanism can contain a blade configured to cut aretaining strap, where cutting the retaining strap triggers the launchof a drogue. The blade can be attached to a mass and a pivot point suchthat the blade moves in response to an acceleration (e.g., caused by anLTA envelope failing) and the movement causes the blade to cut theretaining strap. The acceleration can cause a linear or a rotationaldisplacement of a component of the inertial triggering mechanism, whichcauses the blade to move and cut the retaining strap. In some cases, aninertial triggering mechanism can contain a capsule with a bearinginside the capsule, wherein the bearing moves within the capsule inresponse to an acceleration and upon moving actuates a circuit to launchthe drogue (e.g., using a circuit powered by a battery and anelectrically fired squib). In some cases, a drogue can be deployedmanually prior to a planned descent using a triggering mechanismdescribed herein (e.g., by firing a squib in response to a providedelectrical signal). In the case of manual deployment, the drogues may bedeployed before, during or after a flight termination system cuts one ormore holes in the LTA envelope to terminate the LTA vehicle flight. Insome cases, it may be beneficial to deploy the drogues before the LTAvehicle begins to descend too quickly, since the dynamic pressure athigh descent velocities can damage the drogue deployment mechanismsrendering the drogues unable to deploy.

In some cases, the riser is initially in a coiled state, wherein one endof the riser is attached to the carrier, the other end is attached(directly or indirectly) to the apex of the LTA vehicle, and the coiledriser is contained in a housing (e.g., a riser drum) attached to thecarrier. In such cases, the majority of the riser travels with thedrogue after the drogue is launched, and unspools from the riser drum onthe drogue carrier. In other cases, the riser is coiled and the coiledriser is contained in a housing (e.g., a riser drum) attached to the LTAvehicle apex. In these cases, the majority of the riser stays with theLTA vehicle after the drogue is launched, and unspools from the riserdrum attached to the LTA vehicle.

In some embodiments, the riser drum contains a mechanism for containingthe riser prior to drogue deployment in order to prevent the riser fromuncoiling (i.e., unspooling) prematurely (e.g., during drogue deploymentsystem assembly, or during an LTA vehicle flight prior to flighttermination). For example, the riser coil can be contained using a clipthat releases when the drogue is deployed allowing the riser to begin tounspool. An extra riser piece (e.g., a service loop) can also be used toallow the coiled riser to begin to unspool from the riser drum upondrogue deployment. In some cases, the riser can be held in a coiledstate using a stitch of thread (i.e., a rip stitch) that is configuredto come undone when the drogue is deployed and the riser begins tounspool.

Example Systems

FIG. 1 is a simplified schematic of an example of a portion of an LTAvehicle 100 in side view, comprising a drogue deployment system. Thedrogue deployment system contains two drogues 110 a and 110 b, and iscoupled to an apex plate 102 of the LTA vehicle 100. In some examples,LTA vehicle 100 may be a passive vehicle, such as a balloon orsatellite, wherein most of its directional movement is a result ofenvironmental forces, such as wind and gravity. In other examples, theLTA vehicle 100 may be actively propelled. In some embodiments, LTAvehicle 100 communicates with a ground station (not shown). FIG. 1 onlyshows a portion of LTA vehicle 100, which in this embodiment furtherincludes balloon 101, apex plate 102, and tendons 107. In some examples,apex plate 102 may provide structural and electrical connections andinfrastructure. Apex plate 102 may be positioned at the apex of balloon101 and may serve to couple together various parts of balloon 101, forexample using tendons 107. In some examples, apex plate 102 may includea flight termination unit, such as one or more blades and an actuator toselectively cut a portion and/or a layer of balloon 101 to initiate adescent of LTA vehicle 100. The LTA vehicle 100 may include structuraland electrical connections and infrastructure, including components(e.g., fans, valves, actuators, etc.) used to, for example, add andremove air from balloon 101 (i.e., in some examples, balloon 101 mayinclude an interior ballonet within its outer, more rigid shell that isinflated and deflated), causing balloon 101 to ascend or descend.Balloon 101 may comprise a balloon envelope containing lightweightand/or flexible latex or rubber materials (e.g., polyethylene,polyethylene terephthalate, chloroprene) and tendons 107 (e.g., attachedat one end to apex plate 102 and at another end to a portion of the LTAvehicle 100 below the balloon 101) to provide strength to the balloonstructure. In various embodiments, balloon 101 may be non-rigid,semi-rigid, or rigid.

The drogues 110 a and 110 b in this example are configured to bedeployed in directions 122 a and 122 b, respectively, and at angles 124a and 124 b, respectively. The angles 124 a and 124 b are defined from ahorizontal plane 120. The horizontal plane 120 intersects the apex plate102, and is approximately parallel to the apex plate 102 (e.g., isapproximately parallel to a major surface or a major dimension of theapex plate 102, which are approximately parallel to direction x in FIG.1). As described above, the angles 124 a and 124 b are acute angles fromthe horizontal plane 120 intersecting the apex of the LTA vehicle.Angles 124 a and 124 b can be from 0° to 90° above horizontal plane 120,from 0° to 60° above horizontal plane 120, from 0° to 30° abovehorizontal plane 120, or from about 30° to about 50° above thehorizontal plane, or at about 40° above the horizontal plane, where thedirection “above” is shown by direction z in FIG. 1. Directions 122 aand 122 b can be substantially horizontal (e.g., from 0° to 45° abovehorizontal plane 120) directions from the apex of the LTA vehicle, insome embodiments.

The drogue deployment system shown in FIG. 1 contains two drogues 110 aand 110 b, which are arranged to deploy in directions 122 a and 122 b(e.g., substantially horizontally), and substantially opposite eachother, from the apex of LTA vehicle 100. In some embodiments, thesubstantially horizontal direction of deployment can prevent the droguesfrom falling back, or from being pulled back, onto the apex plate 102 ofthe LTA vehicle 100 prior to the drogue parachutes opening. Deployingthe two drogues 110 a and 110 b in opposing directions (e.g., atapproximately the same time) balances the forces between the deployingdrogues, which minimizes the need for other mechanisms to balance theforce of deploying any one drogue. In this example, the drogues arepositioned with an interval of 180° between them. In the case where thedrogue deployment angles are 0° from the horizontal plane 120, then thedrogue deployment forces can be cancelled out (or approximately cancelout, or almost completely cancel out, or largely cancelled out). Incases where the drogue deployment angles are greater than 0° above thehorizontal plane 120, then the horizontal components (e.g., thoseapproximately parallel with horizontal plane 120) of the droguedeployment forces can be cancelled out (or approximately cancel out, oralmost completely cancel out, or largely cancelled out), however, therewill still be an overall vertical (i.e., perpendicular to the horizontalplane 120) reaction force that cannot be completely cancelled out. Insome cases, the vertical components of the reaction forces push againstthe envelope, which provides a significant resistance in the verticaldirection, and no significant displacement of the balloon vehicle in thevertical direction occurs. In contrast, horizontal reaction forces(e.g., from drogue deployment forces that are not balanced) can causesignificant displacement of the LTA vehicle.

FIGS. 2A, 2B and 2C are simplified schematics of different examples ofapex plates 202 as viewed from above, each containing multiple drogueswhich are arranged to deploy in directions with acute angles from ahorizontal plane from an apex of an LTA vehicle (e.g., in directionssimilar to 122 a and 122 b shown in FIG. 1, or substantiallyhorizontally), such that the drogue deployment forces (or the horizontalcomponents of the drogue deployment forces) can be balanced. FIG. 2Ashows an example with three drogues 210 a-c arranged in an approximatelyequilateral triangular pattern, such that when all three drogues 210 a-care deployed approximately simultaneously the forces of deployment (orthe horizontal components of the drogue deployment forces) can belargely balanced with one another. The interval 215 between the droguesin this case is approximately 120°. FIG. 2B shows an example with fourdrogues 220 a-d arranged in an approximately rectangular (or square)pattern, such that when all four drogues 220 a-d are deployedapproximately simultaneously the forces of deployment (or the horizontalcomponents of the drogue deployment forces) can be largely balanced withone another. The interval between the drogues in this example isapproximately 90°. FIG. 2C shows an example with six drogues 230 a-farranged in an approximately regular hexagonal pattern, such that whenall six drogues 230 a-f are deployed approximately simultaneously theforces of deployment (or the horizontal components of the droguedeployment forces) can largely be balanced with one another. Theinterval between the drogues in this example is approximately 60°.

FIG. 3 shows a simplified schematic of an example of a portion of adrogue deployment system 300. The portion of the drogue deploymentsystem 300 in this example contains a drogue containing a drogueparachute 310 and a carrier 320, a core 330, a riser drum 340 that holdsa riser coil 350, a launch tube 360, a spring 365, a portion of a droguedeployment mechanism 370, and a support structure 380 coupling thisportion of the drogue deployment system to an apex plate of an LTAvehicle (not shown). The portion of the drogue deployment mechanism 370shown in FIG. 3 includes a squib which is used to deploy the drogue.Other components of the drogue deployment mechanism are shown in FIG. 4and are described further herein.

FIG. 4 shows a simplified schematic of an example of a portion of adrogue deployment system 400, shown in perspective view. The portion ofthe drogue deployment system 400 in this example contains a carrier 420,a riser drum 440 that holds a riser coil 450, a drogue deploymentmechanism 470, a support structure 480 coupling this portion of thedrogue deployment system to an apex plate of an LTA vehicle (not shown),and a safety pin 490. The drogue deployment mechanism 470 in thisexample contains a squib 472 with a hole 473, a strap 474, and prongs476. The strap 474 is coupled to the core (not shown), goes under prongs476 in the support structure 480, and is fed through a hole 473 in thesquib 472, such that the strap holds the core to the support structure480 and the core holds the spring in a compressed state. To deploy thedrogue, the squib 472 fires, which cuts the strap 474 thereby releasingthe core from the support structure 480, which allows the spring todecompress and the spring pushes the core off of the launch tubelaunching the drogue. For example, the squib can contain a hard wedgeand the strap can be seated on a backing plate within the hole 473, suchthat when the squib fires the strap is cut by the hard wedge. In otherembodiments, the carrier or another component can be used to hold thespring in a compressed state, and the drogue deployment mechanism canwork similarly to the system described above using a strap that holdsthe carrier or other component to the support structure 480. Forexample, a different component (rather than a strap) can be used to holdthe core (or carrier) in place and the spring in a compressed state,such as a clip or a pin. In such cases, the drogue deployment mechanismcan release the component (e.g., unclip the clip or remove the pin) torelease the core and allow the spring to decompress. The safety pin 490has been removed prior to loading the carrier onto the launch tube andcore. The safety pin 490 was inserted through the launch tube at aposition above the top of the core to prevent the drogue from launchingprematurely.

FIGS. 5A-5D are simplified schematics showing an example of a droguedeployment from an LTA vehicle at different instances in time. FIGS.5A-5D contain an LTA vehicle envelope 501 (e.g., a balloon), an apexplate 502, two drogues 510 and 512, a drogue parachute 515, a carrier520, a riser 550, a coupling 555 between one end of the riser and theapex plate 502, and a spring 565.

FIG. 5A shows two drogues 510 and 512 before deployment, as viewed froma perspective near the center of the apex plate 502, such that bothdrogues in the figure are on one side of the apex plate 502 of the LTAvehicle. FIG. 5B shows one drogue shortly after deployment. In FIG. 5B,a drogue deployment mechanism (not shown) has been triggered and thecarrier 520 has been deployed due to the force from the spring 565decompressing. The riser 550 has begun to uncoil from the drogue 510(e.g., from a riser drum), and the coupling 555 between one end of theriser and the apex plate 502 is also visible. The parachute 515 hasmoved with respect to the carrier 520 at this point (shortly afterdeployment), but has not begun to open. FIG. 5C shows the drogue 510after it has moved away from the apex plate of the LTA vehicle and amajority of the riser 550 has been unspooled from the drogue, but theparachute 515 is still not open. FIG. 5D shows the drogue 510 after thedrogue parachute 515 has been opened.

FIGS. 6A-6B are simplified schematic diagrams of example LTA unmannedaerial vehicle (UAV) systems incorporating the present drogue deploymentsystems, in accordance with some embodiments.

In FIG. 6A, there is shown a diagram of system 600 for navigation ofaerial vehicle 620 a comprising a drogue deployment system. The droguedeployment system contains two drogues 610 a and 610 b, and is coupledto an apex plate 602 of the LTA vehicle 100. In some examples, aerialvehicle 620 a may be a passive vehicle, such as a balloon or satellite,wherein most of its directional movement is a result of environmentalforces, such as wind and gravity. In other examples, aerial vehicles 620a may be actively propelled. In an embodiment, system 600 may includeaerial vehicle 620 a and ground station 614. In this embodiment, aerialvehicle 620 a further includes balloon 601 a, plate 602, altitudecontrol system (ACS) 603 a, connection 604 a, joint 605 a, actuationmodule 606 a, and payload 608 a. In some examples, plate 602 may providestructural and electrical connections and infrastructure. Plate 602 maybe positioned at the apex of balloon 601 a and may serve to coupletogether various parts of balloon 601 a, for example using tendons 607.In other examples, plate 602 also may include a flight termination unit,such as one or more blades and an actuator to selectively cut a portionand/or a layer of balloon 601 a. ACS 603 a may include structural andelectrical connections and infrastructure, including components (e.g.,fans, valves, actuators, etc.) used to, for example, add and remove airfrom balloon 601 a (i.e., in some examples, balloon 601 a may include aninterior ballonet within its outer, more rigid shell that is inflatedand deflated), causing balloon 601 a to ascend or descend, for example,to catch stratospheric winds to move in a desired direction. Balloon 601a may further comprise a balloon envelope comprised of lightweightand/or flexible latex or rubber materials (e.g., polyethylene,polyethylene terephthalate, chloroprene), tendons 607 (e.g., attached atone end to plate 602 and at another end to ACS 603 a) to providestrength to the balloon structure, a ballonet, and other structuralcomponents. In various embodiments, balloon 601 a may be non-rigid,semi-rigid, or rigid.

Connection 604 a may structurally, electrically, and communicatively,connect balloon 601 a and/or ACS 603 a to various components comprisingpayload 608 a. In some examples, connection 604 a may provide two-waycommunication and electrical connections, and even two-way powerconnections. Connection 604 a may include a joint 605 a, configured toallow the portion above joint 605 a to pivot about one or more axes(e.g., allowing either balloon 601 a or payload 608 a to tilt and turn).Actuation module 606 a may provide a means to actively turn payload 608a for various purposes, such as improved aerodynamics, facing or tiltingsolar panel(s) 609 a advantageously, directing payload 608 a andpropulsion units (e.g., propellers 607 in FIG. 6B) for propelled flight,or directing components of payload 608 a advantageously.

Payload 608 a may include solar panel(s) 609 a, avionics chassis 610 a,broadband communications unit(s) 611 a, and terminal(s) 612 a. Solarpanel(s) 609 a may be configured to capture solar energy to be providedto a battery or other energy storage unit, for example, housed withinavionics chassis 610 a. Avionics chassis 610 a also may house a flightcomputer (e.g., to electronically control various systems within the UAV620 a), a transponder, along with other control and communicationsinfrastructure (e.g., a computing device and/or logic circuit configuredto control aerial vehicle 620 a). Communications unit(s) 611 a mayinclude hardware to provide wireless network access (e.g., LTE, fixedwireless broadband via 5G, Internet of Things (IoT) network, free spaceoptical network or other broadband networks). Terminal(s) 612 a maycomprise one or more parabolic reflectors (e.g., dishes) coupled to anantenna and a gimbal or pivot mechanism (e.g., including an actuatorcomprising a motor). Terminal(s) 612(a) may be configured to receive ortransmit radio waves to beam data long distances (e.g., using themillimeter wave spectrum or higher frequency radio signals). In someexamples, terminal(s) 612 a may have very high bandwidth capabilities.Terminal(s) 612 a also may be configured to have a large range of pivotmotion for precise pointing performance. Terminal(s) 612 a also may bemade of lightweight materials.

In other examples, payload 608 a may include fewer or more components,including propellers 607 as shown in FIG. 6B, which may be configured topropel aerial vehicles 620 a-b in a given direction. In still otherexamples, payload 608 a may include still other components well known inthe art to be beneficial to flight capabilities of an aerial vehicle.For example, payload 608 a also may include energy capturing units apartfrom solar panel(s) 609 a (e.g., rotors or other blades (not shown)configured to be spun by wind to generate energy). In another example,payload 608 a may further include or be coupled to an imaging device(e.g., a star tracker. IR, video, Lidar, and other imaging devices, forexample, to provide image-related state data of a balloon envelope,airship hull, and other parts of an aerial vehicle). In another example,payload 608 a also may include various sensors (not shown), for example,housed within avionics chassis 610 a or otherwise coupled to connection604 a or balloon 601 a. Such sensors may include Global PositioningSystem (GPS) sensors, wind speed and direction sensors such as windvanes and anemometers, temperature sensors such as thermometers andresistance temperature detectors, speed of sound sensors, acousticsensors, pressure sensors such as barometers and differential pressuresensors, accelerometers, gyroscopes, combination sensor devices such asinertial measurement units (IMUs), light detectors, light detection andranging (LIDAR) units, radar units, cameras, other image sensors, andmore. These examples of sensors are not intended to be limiting, andthose skilled in the art will appreciate that other sensors orcombinations of sensors in addition to these described may be includedwithout departing from the scope of the present disclosure.

Ground station 614 may include one or more server computing devices 615a-n, which in turn may comprise one or more computing devices (e.g., acomputing device and/or logic circuit configured to control aerialvehicle 620 a). In some examples, ground station 614 also may includeone or more storage systems, either housed within server computingdevices 615 a-n, or separately. Ground station 614 may be a datacenterservicing various nodes of one or more networks.

FIG. 6B shows a diagram of system 650 for navigation of aerial vehicle620 b. All like-numbered elements in FIG. 6B are the same or similar totheir corresponding elements in FIG. 6A, as described above (e.g.,balloon 601 a and balloon 601 b may serve the same function, and mayoperate the same as, or similar to, each other). In some examples,balloon 601 b may comprise an airship hull or dirigible balloon. In thisembodiment, aerial vehicle 620 b further includes, as part of payload608 b, propellers 607, which may be configured to actively propel aerialvehicle 620 b in a desired direction, either with or against a windforce to speed up, slow down, or re-direct, aerial vehicle 620 b. Inthis embodiment, balloon 601 b also may be shaped differently fromballoon 601 a, to provide different aerodynamic properties. In thisembodiment, tendons (not shown) may also be present to couple the apexplate 602 to the other components of the aerial vehicle (e.g., to theACS 603 b, to the connection 604 b, or to the joint 605 b). In somecases of this embodiment, there can be more than one plate (similar toapex plate 602) with a drogue deployment system coupled to each plate.For example, a first plate with a first drogue deployment system can becoupled to the nose (or the leading edge) of the envelope 601 b ofaerial vehicle 620 b, and a second plate with a second drogue deploymentsystem can be coupled to the tail (or the trailing edge) of the envelope601 b of aerial vehicle 620 b. In other cases, there can be a singleplate, which can be coupled to a different location of envelope 601 b ofaerial vehicle 620 b than the apex plate 602 shown in FIG. 6B. Forexample, the plate can be coupled to the tail (or the trailing edge) ofthe envelope 601 b of aerial vehicle 620 b, and before deploying thedrogues, the aerial vehicle 620 b can maneuver such that the nose of theaerial vehicle is pointed downwards (toward the ground) and the droguescan be deployed upwards from the tail of the envelope 601 b of theaerial vehicle 620 b.

As shown in FIGS. 6A-6B, aerial vehicles 620 a-b may be largelywind-influenced aerial vehicles, for example, balloons carrying apayload (with or without propulsion capabilities) as shown. However,those skilled in the art will recognize that the systems disclosedherein may similarly apply and be usable by various other types of LTAaerial vehicles.

Example Methods

In some embodiments, a method 700 of deploying drogues from an LTAvehicle includes the steps shown in FIG. 7. At step 702 of method 700,an LTA vehicle is provided comprising an envelope and a droguedeployment system coupled to an apex of the envelope of the LTA vehicle(e.g., using an apex plate). At step 704, two or more drogues aredeployed from the drogue deployment system directed outward from theapex in acute angles (e.g., from 0° to 45°) from a horizontal plane. Thedrogue deployment in step 704 may be initiated manually or automaticallyusing any of the mechanisms described herein. The drogues deployed instep 704 each contain a weighted carrier and a drogue parachute. In step706, the weighted carriers are used to stabilize each of the drogues.For example, the weighted carriers can assist with orienting the drogues(e.g., such that the parachutes can open above the carrier with respectto the force of gravity and catch passing air to inflate) after thedrogues are deployed and before the drogue parachutes open. At step 708,the parachutes are opened from the drogues. The drogue parachutes may beopened in step 708 using any of the mechanisms described herein. At step710, the envelope is prevented from collapsing on a payload or otherunderlying structure of the LTA vehicle prematurely using the openeddrogue parachutes. The drogue parachutes can also increase the descentvelocity of the LTA vehicle in the initial stages of descent (i.e.,before a main parachute is opened) by applying a force that streamlinesthe envelope. In some cases, an additional step after step 710 may beadded in which one or more main parachutes are deployed (e.g., onecoupled to the payload and one coupled to the envelope) to slow thedescent velocity of the LTA vehicle

In some embodiments, a method 800 of loading drogues in a droguedeployment system for an LTA vehicle includes the steps shown in FIG. 8.At step 802, a core is placed around an outer circumference of a launchtube and around a spring, where the core compresses the spring. In somecases, the launch tube is coupled to the apex plate using a supportstructure, and the launch tube is directed outward from the apex in anacute angle from a horizontal plane. At step 804, a strap is coupled tothe core and to a drogue deployment mechanism, where the strap holds thecore in place and the spring in a compressed state. For example, thedrogue deployment mechanism 470 shown in FIG. 4 can be used to performthis step by coupling the strap 474 (which is connected to a core thatis not shown) to the squib 472. In other variations of method 800, adifferent component (rather than a strap) can be used to hold the corein place and the spring in a compressed state, such as a clip or a pin.In such cases, the drogue deployment mechanism can release the component(e.g., unclip the clip or remove the pin) to release the core and allowthe spring to decompress. In some cases, after step 804 and before step806, a safety pin (e.g., element 490 in FIG. 4) can be inserted (e.g.,through holes in the core and the launch tube) as an extra precaution toprevent the spring from decompressing prematurely. In some cases, thesafety pin can be removed before step 806. In step 806, a drogue isloaded onto the core, where the drogue comprises a drogue parachute anda carrier. In some cases, the carrier can be coupled to the core suchthat the core travels with the drogue after the drogue is deployed,while in other cases, the core can push the drogue off of the launchtube, but does not travel with the drogue after deployment (e.g., thecore can fall away after the drogue is deployed, in some cases). At step808, a riser is coupled from the drogue to the support structure. Asdescribed herein, this method may be implemented on an LTA vehiclecomprising an envelope and a drogue deployment system coupled to an apexof the envelope.

While specific examples have been provided above, it is understood thatthe present invention can be applied with a wide variety of inputs,thresholds, ranges, and other factors, depending on the application. Forexample, the time frames and ranges provided above are illustrative, butone of ordinary skill in the art would understand that these time framesand ranges may be varied or even be dynamic and variable, depending onthe implementation.

As those skilled in the art will understand, a number of variations maybe made in the disclosed embodiments, all without departing from thescope of the invention, which is defined solely by the appended claims.It should be noted that although the features and elements are describedin particular combinations, each feature or element can be used alonewithout other features and elements or in various combinations with orwithout other features and elements.

1. (canceled)
 2. A drogue deployment system for a lighter than air (LTA)vehicle, the drogue deployment system comprising: a launch tubeconfigured for coupling with an LTA vehicle; a biasing element coupledalong the launch tube; a drogue assembly coupled around the launch tube,wherein the drogue assembly includes: a carrier having a cavity, thebiasing element and the launch tube are within the cavity; wherein thebiasing element is deformed between the carrier and the launch tube; anda drogue parachute coupled around the carrier; and a tether coupledbetween the drogue parachute and the launch tube, the tether isconfigured to anchor the drogue parachute to the LTA vehicle.
 3. Thedrogue deployment system of claim 2 comprising a core coupled with thelaunch tube in a loaded configuration, and in the loaded configuration:the core is statically fastened to the launch tube with a droguedeployment mechanism; and wherein the deformed biasing element isdeformed with the statically fastened core.
 4. The drogue deploymentsystem of claim 3, wherein the core is movably coupled with the launchtube in a deployed configuration, and in the deployed configuration: thedrogue deployment mechanism releases the core; the deformed biasingelement transitions toward a non-deformed condition; and the drogueassembly is launched laterally relative to the launch tube according tothe biasing element transition.
 5. The drogue deployment system of claim3, wherein the carrier includes the core within the cavity.
 6. Thedrogue deployment system of claim 2, wherein the tether is positionedwithin a riser drum coupled with the drogue assembly.
 7. The droguedeployment system of claim 6, wherein the tether is coiled within theriser drum.
 8. The drogue deployment system of claim 2 comprising theLTA vehicle, the LTA vehicle includes an envelope and a payload; whereinthe launch tube is directed away from the envelope.
 9. The droguedeployment system of claim 8, wherein a plurality of drogue deploymentsystems are coupled with the envelope.
 10. A lighter than air (LTA)vehicle comprising: an envelope; a payload coupled with the envelope;one or more drogue deployment systems coupled with the envelope, andeach of the drogue deployment systems includes: a launch tube; a biasingelement coupled along the launch tube; a drogue assembly coupled aroundthe launch tube, wherein the drogue assembly includes: a carrier havinga cavity, the biasing element and the launch tube are within the cavity;a drogue parachute coupled with the carrier; and wherein the biasingelement is configured to launch the carrier and the drogue parachuteaway from the envelope; and a tether coupled between the drogueparachute and the envelope, the tether is configured to anchor thedrogue parachute to the envelope.
 11. The LTA vehicle of claim 10,wherein the one or more drogue deployment systems include a core coupledwith the launch tube in a loaded configuration and a drogue deploymentmechanism, and in the loaded configuration: the core is staticallyfastened to the launch tube with the drogue deployment mechanism; andwherein the biasing element is deformed with the statically fastenedcore.
 12. The LTA vehicle of claim 11, wherein the core is movablycoupled with the launch tube in a deployed configuration, and in thedeployed configuration: the drogue deployment mechanism releases thecore; the deformed biasing element is released and transitions toward anon-deformed condition; and the drogue assembly is launched away fromthe launch tube according to the biasing element transition.
 13. The LTAvehicle of claim 11, wherein the carrier includes the core within thecavity.
 14. The LTA vehicle of claim 10, wherein the tether ispositioned within a riser drum coupled with one of the drogue assemblyor the launch tube.
 15. The LTA vehicle of claim 14, wherein the tetheris coiled within the riser drum.
 16. The LTA vehicle of claim 10,wherein the one or more drogue deployments systems are coupled with anapex plate coupled with the envelope.
 17. The LTA vehicle of claim 16,wherein the one or more drogue deployments systems includes a pluralityof drogue deployment systems and each of the drogue deployment systemsare distributed around the apex plate.
 20. A method for deploying adrogue parachute comprising: releasing a biasing element coupled along alaunch tube with a drogue deployment mechanism; launching the drogueparachute from the launch tube, launching includes: transitioning thereleased biasing element from a deformed condition toward a non-deformedcondition; driving a carrier from the launch tube according to thetransition of the biasing element between the deformed and non-deformedconditions, wherein the drogue parachute is coupled around the carrier;deploying a tether between the launched drogue parachute and the launchtube as the drogue parachute is moving away from the launch tube. 21.The method of claim 20, wherein transitioning the released biasingelement from the deformed condition toward the non-deformed conditionincludes transitioning a coil spring from a compressed condition towarda non-compressed condition.
 22. The method of claim 20, wherein thelaunch tube is within the carrier, and driving the carrier from thelaunch tube includes sliding the carrier along the launch tube.
 23. Themethod of claim 20 comprising unwrapping the drogue parachute fromaround the carrier.
 24. The method of claim 20, wherein the tether iscoiled within a riser drum, and deploying the tether includes uncoilingthe tether from the riser drum.
 25. The method of claim 20 comprising aLTA vehicle including an envelope and a payload, and the launch tube iscoupled with the envelope, wherein launching the drogue parachuteincludes launching the drogue parachute away from the envelope.